optical transmittance
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2022 ◽  
Vol 9 ◽  
Author(s):  
Edigar Muchuweni ◽  
Edwin T. Mombeshora ◽  
Bice S. Martincigh ◽  
Vincent O. Nyamori

In recent years, carbon-based materials, particularly carbon nanotubes (CNTs), have gained intensive research attention in the fabrication of organic solar cells (OSCs) due to their outstanding physicochemical properties, low-cost, environmental friendliness and the natural abundance of carbon. In this regard, the low sheet resistance and high optical transmittance of CNTs enables their application as alternative anodes to the widely used indium tin oxide (ITO), which is toxic, expensive and scarce. Also, the synergy between the large specific surface area and high electrical conductivity of CNTs provides both large donor-acceptor interfaces and conductive interpenetrating networks for exciton dissociation and charge carrier transport. Furthermore, the facile tunability of the energy levels of CNTs provides proper energy level alignment between the active layer and electrodes for effective extraction and transportation of charge carriers. In addition, the hydrophobic nature and high thermal conductivity of CNTs enables them to form protective layers that improve the moisture and thermal stability of OSCs, thereby prolonging the devices’ lifetime. Recently, the introduction of CNTs into OSCs produced a substantial increase in efficiency from ∼0.68 to above 14.00%. Thus, further optimization of the optoelectronic properties of CNTs can conceivably help OSCs to compete with silicon solar cells that have been commercialized. Therefore, this study presents the recent breakthroughs in efficiency and stability of OSCs, achieved mainly over 2018–2021 by incorporating CNTs into electrodes, active layers and charge transport layers. The challenges, advantages and recommendations for the fabrication of low-cost, highly efficient and sustainable next-generation OSCs are also discussed, to open up avenues for commercialization.


Crystals ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 62
Author(s):  
Hussein Alrobei ◽  
Adnan Maqbool ◽  
Muhammad Asif Hussain ◽  
Rizwan Ahmed Malik ◽  
Muhammad Ramzan Abdul Karim ◽  
...  

Nanostructured materials with optical transmittance with sufficient electrical conductivity are feasible for the transparent electrical devices and optoelectronic applications. Copper (Cu) possesses inherent superior electrical conductivity. Cu thin films on glass substrates provide the basic design understanding of the transparent electrodes for humidity sensors and solar cells applications. To understand the fundamental fabrication and electrical properties, a single-step facile fabrication approach was applied for Cu nanofilms through the DC sputtering method. Correlation of thickness of Cu nanofilms with optical and electrical properties was established. Parameters such as current, voltage, vacuum pressure, and time of coating were varied to develop different thickness of metal coating. Under optimized conditions of 10−1 torr vacuum, 1.45 KV voltage, and 4–6 min coating time, a conductive path is successfully established. A 1 min coated sample demonstrated resistance of 4000 ohm and conductance of a 6 min coated sample was raised to 56 m-mho. A higher surge of voltage assisted the production of relatively thick and uniform coatings with the crystallite size of 12 nm. The average coating thickness of 19.8 nm and roughness of 4.5 nm was obtained for a 5 min coated sample through AFM analysis. Further, it was observed that uniform nanostructured coating is essential to establish a mean free path of coated particles.


Author(s):  
SHEHLA HONEY ◽  
JAMIL ASIM ◽  
KAVIYARASU KASINATHAN ◽  
MAAZA MALIK ◽  
SHAHZAD NASEEM ◽  
...  

Electrical conductivity and optical transmittance of nickel nanowire (Ni-NW) networks are reported in this work. The Ni-NWs were irradiated with 3.5, 3.8 and 4.11[Formula: see text]MeV proton (H[Formula: see text]) ions at room temperature. The electrical conductivity of Ni-NW networks was observed to increase with the increase in beam energies of H[Formula: see text] ions. With the increase in ions beam energies, electrical conductivity increases and this may be attributed to a reduction in the wire–wire point contact resistance due to the irradiation-induced welding of NWs. Welding is probably initiated due to H[Formula: see text] ion-irradiation induced heating effect that also improved the crystalline quality of the NWs. After ion beam irradiation, localized heat is generated in the NWs due to ionization which was also verified by SRIM simulation. Optical transmittance is increased with increase in the energy of H[Formula: see text] ions. The Ni-NW networks subjected to an ion beam irradiation to observe corresponding changes in electrical conductivity and optical transparencies are promising for various nanotechnological applications, such as highly transparent and conducting electrodes.


Polymers ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 68
Author(s):  
David Ibarra ◽  
Raquel Martín-Sampedro ◽  
Bernd Wicklein ◽  
Antonio M. Borrero-López ◽  
Concepción Valencia ◽  
...  

In order to identify new sustainable sources for producing cellulose nanofibers (CNFs), fast-growing poplar (Populus alba L.) wood was evaluated herein. For that purpose, bleached poplar kraft pulp was produced and submitted to TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl radical) mediated oxidation (TEMPO-ox) chemical pretreatment followed by microfluidization. The resulting CNFs were thoroughly characterized, including a rheological study at different pH values. Poplar CNFs showed properties comparable to eucalypt CNFs (reference material for CNFs production), showing high carboxylate content (1048 ± 128 µmol g−1), fibrillation yield (87.3% ± 8.1%), optical transmittance (83% at 700 nm) and thermal stability (up to more than 200 °C). Regarding the rheological study, whereas pH from 4 to 10 did not produce significant changes in rheological behavior, a reduction of pH down to 1 led to an order-of-magnitude increase on the viscoelastic functions. Therefore, poplar CNF shows potential in the pH-sensitive hydrogels application field. Finally, the possible ecotoxicity of poplar CNF was assessed. The decrease in cell viability was very low so that only concentrations causing a 10% cytotoxicity could be calculated for the assay detecting alterations in cell metabolism (10 µg mL−1) and plasma membrane integrity (60 µg mL−1).


Coatings ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 19
Author(s):  
Chuen-Lin Tien ◽  
Hong-Yi Lin ◽  
Kuan-Sheng Cheng ◽  
Chun-Yu Chiang ◽  
Ching-Ying Cheng

This study presents a multilayer design and fabrication of an optical notch filter for enhancing visual quality. A cost-effective multilayer design of notch filter with low surface roughness and low residual stress is proposed. A 9-layer notch filter composed of SiO2 and Nb2O5 with a central wavelength of 480 nm is prepared by electron beam evaporation combined with ion-assisted deposition. The optical transmittance, residual stress, and surface morphology are measured by a UV/VIS/NIR spectrophotometer, Twyman-Green interferometer and field emission scanning electron microscopy (FE-SEM). The transmittance of the notch filter at the central wavelength is above 15%, and the average transmittance of the transmission band is about 80%. The residual stress of the notch filter is −0.235 GPa, and the root mean square surface roughness is 1.85 nm. For improving the visual quality, a good image contrast can be obtained by observing the microscopic image using the proposed notch filter.


Crystals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1583
Author(s):  
Yanfei Dong ◽  
Dingwang Yu ◽  
Guochao Li ◽  
Yulin Cao ◽  
Youde Ruan ◽  
...  

The design of an optically transparent and flexible metamaterial absorber was presented and fabricated. For this purpose, we use two different patterned silver nanowire films separated by the space layer, forming a transparent sandwiched structure with an ultrathin thickness. By analyzing the equivalent circuit model and distribution of electric field and current, the absorption physical mechanism has been theoretically investigated. The results show that the structure can achieve above 0.8 absorptions from 6 GHz to 18 GHz, and at the same time, this absorber also can obtain wide-angle property. The optical transmittance of the fabricated absorber exceeds 82% in the visible band. The results demonstrate that transparency and flexibility are the additional benefits that make the proposed absorber suitable for various potential applications.


Research ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Qianying Lu ◽  
Yunlei Zhou ◽  
Xiangfei Yin ◽  
Shitai Cao ◽  
Xiaoliang Wang ◽  
...  

In contrast to ionically conductive liquids and gels, a new type of yield-stress fluid featuring reversible transitions between solid and liquid states is introduced in this study as a printable, ultrastretchable, and transparent conductor. The fluid is formulated by dispersing silica nanoparticles into the concentrated aqueous electrolyte. The as-printed features show solid-state appearances to allow facile encapsulation with elastomers. The transition into liquid-like behavior upon tensile deformations is the enabler for ultrahigh stretchability up to the fracture strain of the elastomer. Successful integrations of yield-stress fluid electrodes in highly stretchable strain sensors and light-emitting devices illustrate the practical suitability. The yield-stress fluid represents an attractive building block for stretchable electronic devices and systems in terms of giant deformability, high ionic conductivity, excellent optical transmittance, and compatibility with various elastomers.


Coatings ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1513
Author(s):  
Chuen-Lin Tien ◽  
Hong-Yi Lin ◽  
Kuan-Sheng Cheng ◽  
Chih-Kai Chang

We present a new laser protective lens based on a multilayered notch filter design with low residual stress and low surface roughness. An18-layer notch filter was prepared by electron beam evaporation with an ion-assisted deposition technique, which was composed of SiO2 and Nb2O5 with a center wavelength of 532 nm. The optical transmittance, residual stress, surface roughness, and surface morphology were measured by a UV/VIS/NIR spectrophotometer, Twyman–Green interferometer, scanning probe microscope, Linnik microscopic interferometer, and field-emission scanning electron microscopy (FE-SEM). The transmittance of the notch filters at center wavelength is 0.2%, and the average transmittance of the transmission band is about 70%. The residual stress of the notch filter is −0.298 GPa, and the root mean square surface roughness is 1.88 nm. The experimental results show that the optical transmittance meets the design requirements.


Author(s):  
Mélanie Delort ◽  
Damien Ali Hamada FAKRA ◽  
Bruno Mallet-Damour ◽  
Jean Claude Gatina

Abstract Studying thermo-optical (i.e., thermal conductivity, optical re ectance, optical transmittance, and optical absorbance) properties of construction materials is essential for improving human comfort within a building. Typically, these properties are measured independently using specific equipment. The emerging of new innovative construction structures, such as translucent materials, makes the experimental characterization of these properties more challenging to observe. Recently, a new device, called MultiCoefMeter (McM), which rapidly and simultaneously measures all these properties, has been created. The study described in this article covers the calculation technique for estimating measurement uncertainties linked to morphology, the component parts, and the physical formula of the experimental apparatus. The measurement uncertainty estimates are obtained from knowledge of the color of the system's walls, placement, and form of the McM components, placement of measurement sensors, and the application of measurement collection equipment. Therefore, a thorough calculation analysis was performed on the sub-systems. Calculations are divided between two categories: those based on mathematical tools and information given by the makers, and those based on experimental observations obtained during reliability testing. These uncertainties originate from statistical tools, geometric tolerance of the system, comparison with standards, and the error propagation laws of the physical models link with the device. All these uncertainties were summed up and given a global value, no more than 5%, conforming to the ASTM standard (E1225). Finally, a general method to quantify measurement uncertainty value of any experimental device was proposed.


Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7435
Author(s):  
Zitao Shi ◽  
Qilong Yuan ◽  
Yuezhong Wang ◽  
Kazuhito Nishimura ◽  
Guojian Yang ◽  
...  

Bulk diamonds show great potential for optical applications such as for use in infrared (IR) windows and temperature sensors. The development of optical-grade bulk diamond synthesis techniques has facilitated its extreme applications. Here, two kinds of bulk single-crystal diamonds, a high-pressure and high-temperature (HPHT) diamond and a chemical vapor deposition (CVD) diamond, were evaluated by Raman spectroscopy and Fourier Transform Infra-Red (FTIR) spectroscopy at a range of temperatures from 80 to 1200 K. The results showed that there was no obvious difference between the HPHT diamond and the CVD diamond in terms of XRD and Raman spectroscopy at 300–1200 K. The measured nitrogen content was ~270 and ~0.89 ppm for the HPHT diamond and the CVD diamond, respectively. The moderate nitrogen impurities did not significantly affect the temperature dependence of Raman spectra for temperature-sensing applications. However, the nitrogen impurities greatly influence FTIR spectroscopy and optical transmittance. The CVD diamond showed higher transmittance, up to 71% with only a ~6% drop at temperatures as high as 873 K. This study shows that CVD bulk diamonds can be used for IR windows under harsh environments.


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